Question: Determine the value of the following complex number power. Your answer will be plotted in orange. $ ({\cos(\frac{1}{2}\pi) + i \sin(\frac{1}{2}\pi)}) ^ {11} $ Re Im
Solution: Let's express our complex number in Euler form first. $ {\cos(\frac{1}{2}\pi) + i \sin(\frac{1}{2}\pi)} = { e^{\pi i / 2}} $ Since $(a ^ b) ^ c = a ^ {b \cdot c}$ $ ({ e^{\pi i / 2}}) ^ {11} = e ^ {11 \cdot (\pi i / 2)} $ The angle of the result is $11 \cdot \frac{1}{2}\pi$ , which is $\frac{11}{2}\pi$ $\frac{11}{2}\pi$ is more than $2 \pi$ . It is a common practice to keep complex number angles between $0$ and $2 \pi$ , because $e^{2 \pi i} = (e^{\pi i}) ^ 2 = (-1) ^ 2 = 1$ . We will now subtract the nearest multiple of $2 \pi$ from the angle. $ \frac{11}{2}\pi - 4\pi = \frac{3}{2}\pi $ Our result is $ e^{3\pi i / 2}$. Converting this back from Euler form, we get $\cos(\frac{3}{2}\pi) + i \sin(\frac{3}{2}\pi)$.